JGOFS/SMP: Data-Based Models of Food Web Structure and Export Flux

浮游生物群落结构和输出通量的数据模型在过去十年中密集的JGOFS调查表明，物理-化学环境强迫、浮游生物群落结构和碳生产（再矿化或输出）的命运之间存在密切联系。然而，这些关系在现有的浮游生物食物网模型中被粗略地描绘出来。目前尚不清楚，要进行适当的模型预测，需要多少关于大小和分类组成的信息，以及不同水体中的群落动态和生物地球化学通量在多大程度上通过共同的组织原则和数量关系联系在一起。本研究的总体目标是促进对调节“光带碳和相关生物活性物质的生产和出口”的因素的机制理解。为了实现这一目标，pi将开发和评估基于数据的浮游生物群落结构模型，并输出热带/亚热带开放海洋生态系统的通量。该项目将侧重于热带和亚热带海洋，这些区域是JGOFS进程和时间序列研究中最具代表性的区域（EqPac、阿拉伯海、HOT、BATS），目前在成熟数据库和支持性实验研究方面最发达。具体目标是：1)建立浮游生物群落结构和营养相互作用的数据约束表示；2)建立夏威夷海洋时间序列（HOT）站点和赤道太平洋铁扰动（IronEx II）后浮游生物群落动态和相关生物地球化学通量模型；3)比较和测试用于较低营养水平相互作用的简单参数化和用于三维耦合模型的输出通量；4)建立一个一般的热带海洋模式，包括对营养供应（阿拉伯海）和铁限制（赤道太平洋）的适当反应；5)研究计算密集型全球环流模式（GCMs）中预测生物现实响应的模式结构和策略。根据在不同热带海洋生态系统中观察到的种群和过程速率的相似性，pi假设这些数据将有助于在具有共同结构和参数的一般热带海洋模式中表示。为了研究在全球模型中捕获基本生物现实所需的最小复杂性水平，他们将统计地检查一个相互关联的模型光谱，所有模型都是根据共同的数据集校准的，但在结构复杂性上有所不同。

Data-Based Models of Plankton Community Structure and Export FluxIntensive JGOFS investigations over the past decade have indicated strong links among physical-chemical environmental forcing, plankton community structure, and the fate of carbon production (remineralization or export). However, these relationships are crudely portrayed in existing plankton food web models. It is presently unclear how much information on size and taxonomic composition is needed for adequate model predictions and to what extent community dynamics and biogeochemical fluxes in different water masses are linked by common organizational principles and quantitative relationships.The overall goal of the proposed research is to contribute to the mechanistic understanding of the factors that regulate "euphotic zone production and export of carbon and related biologically active substances". To accomplish this, the PIs will develop and evaluate data-based models of plankton community structure and export flux for tropical/subtropical open-ocean ecosystems. This project will focus on the tropical and subtropical oceans, areas most strongly represented in JGOFS Process and Time-series studies (EqPac, Arabian Sea, HOT, BATS) and presently most developed in terms of mature databases and supporting experimental studies. The specific objectives are: 1) to develop data-constrained representations of planktonic community structure and trophic interactions; 2) to construct models of temporal plankton community dynamics and associated biogeochemical fluxes at the Hawaii Ocean Time-series (HOT) site and following iron perturbation in the equatorial Pacific (IronEx II); 3) to compare and test simple parameterizations, for lower trophic level interactions and export fluxes for use in 3-D coupled models; 4) to develop a general tropical ocean model that includes appropriate responses to nutrient supply (Arabian Sea) and iron-limitation (Equatorial Pacific); and 5) to examine model structures and strategies for predicting biologically realistic responses in computationally intensive Global Circulation Models (GCMs). Based on observed similarities in the stocks and process rates in diverse tropical oceanic ecosystems, the PIs hypothesize that the data will lend themselves to representation in a general tropical ocean model with common structure and parameters. To investigate the minimum level of complexity required to capture essential biological realities in global models, they will statistically examine an interrelated spectrum of models, all calibrated to common data sets but differing in structural complexity.